导入变量名称空间 [英] Importing variable namespaces

问题描述

是否可以使用这样的变量导入名称空间:

Would it be possible to import namespaces using a variable like this:

$namespace = 'User\Authorization\Certificate';
use $namespace;

很明显，这不会像use语句所期望的那样运行，但是有解决方法吗?

Obviously this won't run as use statement expects a constant but is there a workaround?

发现了一个gem(仅在PHP> 5.3中):class_alias($namespace, alias);与use User\Authorization\Certificate as alias;具有几乎相同的功能，因此将使用它.

Discovered a gem (only in PHP > 5.3): class_alias($namespace, alias); which does pretty much the same thing with use User\Authorization\Certificate as alias; so will be using that.

推荐答案

虽然无法将变量中的名称空间传递给use，但您可以放置名称空间和预期的在变量中使用短"类名，并在大多数需要的地方使用它，例如调用new.

While it isn't possible to pass a namespace in a variable to use, you can place the namespace and the expected "short" class name in a variable and use that in most places where you'd need it, like invoking new.

$namespace = '\foo\bar';
$class = 'baz';
$fully_qualified = $namespace . '\\'. $class; // \foo\bar\baz
$a_foo_bar_baz = new $fully_qualified(...);
var_dump( $a_foo_bar_baz instanceof $fully_qualified ); // true

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